Controlled source electromagnetic surveys have been carried out using horizontal or vertical electric dipole sources for transmitting an EM field, with receivers positioned a distance away from the source to measure the EM field components. The marine Controlled Source Electromagnetic (CSEM) method comprises a horizontal electric dipole (HED) source and receivers that measure the EM field components on the seafloor. In shallow water the horizontal field measurements are affected by magnetotelluric (MT)-noise and the so-called airwave component. In order to avoid MT signals and the airwave component in the data, one can in principle use the measured vertical electric and magnetic field, but inaccurate and unstable directionality of the vertical receiver antennas can lead to quite bad measurements for these components.